The UEFA Champions League is a seasonal association football competition established in 1955.[1] The UEFA Champions League is open to the league champions of all UEFA (Union of European Football Associations) member associations (except Liechtenstein, which has no league competition), as well as to the clubs finishing from second to fourth position in the strongest leagues.[2] Prior to the 1992–93 season, the tournament was named the European Cup.[1] Originally, only the champions of their respective national league and the defending champion of the competition were allowed to participate. However, this was changed in 1997 to allow the runners-up of the stronger leagues to compete as well.[3] The defending champion of the competition did not automatically qualify until the rules were changed in 2005 to allow title holders Liverpool to enter the competition.[4]

Teams that have won the UEFA Champions League three times in a row, or five times overall, receive a multiple-winner badge.[5] Six teams have earned this privilege: Real Madrid, Ajax, Bayern Munich, Milan, Liverpool and Barcelona.[6] Until 2009, clubs that had earned that badge were allowed to keep the European Champion Clubs' Cup and a new one was commissioned;[7] since 2009, the winning team each year has received a full-size replica of the trophy, while the original is retained by UEFA.[8]

A total of 22 clubs have won the Champions League/European Cup. Real Madrid hold the record for the most victories, having won the competition 11 times, including the inaugural competition. They have also won the competition the most times in a row, winning it five times from 1956 to 1960. Juventus have been runners-up the most times, losing six finals. Atlético Madrid is the only team to reach three finals without having won the trophy while Stade de Reims and Valencia have finished as runners-up twice without winning. Spain has provided the most champions, with 16 wins from two clubs.[9] Italy have produced 12 winners from three clubs and England have produced 12 winners from five clubs. English teams were banned from the competition for five years following the Heysel disaster in 1985.[10] The current champions are Real Madrid, who beat Atlético Madrid on penalties in the 2016 final.